A multivariate detection sensor that can detect a physical amount of sound, vibration, pressure or acceleration etc. and a physical amount of light is described in a patent document 1, for example.
The multivariate detection sensor described in the patent document 1 utilizes the combination of an electret capacitor and an optical sensor.
That is, as to a physical amount of sound, vibration, pressure or acceleration etc., the change of an electrostatic capacitance is converted into a voltage etc. and the physical amount of each of these parameters is detected based on the converted value. Further, a physical amount of light is detected by using another sensor different from an electret capacitor type sensor.
Patent Document 1: JP-A-2004-354199 (page 1, FIG. 1).